Automated particle collection off of fan blades into a liquid buffer

ABSTRACT

Fan blades within a fan assembly are rotated in a first rotational direction, thereby generating airflow from above the fan blades downward past the fan blades. Airborne particles adhere to the surface of the fan blades as the air flows past. The fan direction is then reversed maintained at a relatively low rotational rate. A fluid is dispensed onto the hub of the fan blades. Due to the centripetal force of the spinning fan blades, the fluid is spread thin across the top surface of the fan blades and the liquid film washes the blade of the fan, removing particulates from the fan blade. The solution is pushed outward against the inner wall of the fan housing forming a fluid meniscus. The fan speed is increased to push the fluid meniscus into an annular reservoir. The collected fluid is then vacuumed and consolidated into the collection vessel.

FIELD OF THE INVENTION

The invention relates to a method of and apparatus for collectingparticulates. More particularly, the invention relates to collecting airparticles into a liquid buffer.

BACKGROUND OF THE INVENTION

Bio-threat detectors are used to monitor the ambient air to detect thepresence of potentially harmful pathogens. In general, air is drawn intoa detection apparatus, or trigger, where the particulates in the air areevaluated. Airflow into the detection apparatus is typically generatedby a fan within the apparatus. The trigger continuously monitors the airand the individual molecules within a given airflow. Some triggers uselasers to scan the air path to interrogate the particles passingthrough. A harmless particle, such as a dust particle, can bediscriminated from a harmful particle, for example an anthrax spore,because each different type of particle reflects a different wavelengthof light. The laser light reflected of the passing particles is matchedto database of known harmful wavelengths. When a harmful wavelength isdetected, the trigger signals that a potential pathogen is present.However, the specific type of particle is not identified by the trigger.

A confirmation module takes over once the trigger signals the presenceof a possible pathogen. The trigger signal initiates the confirmationmodule into action. The confirmation module identifies the particlesdetected by the trigger. Conventionally, when the trigger goes off, thepotential pathogen is collected and taken to a lab where theconfirmation module performs the analysis. Some detection apparatusesare configured with a secondary fan assembly, such as a muffin fan, suchthat the potential pathogens collect on the fan blades of the secondaryfan assembly as the air flows through the detection apparatus. In suchconfigurations, the secondary fan assembly is activated via the triggersignal. The fan blades or the fan assembly is removed from the detectionapparatus and taken to a laboratory for analysis. At the lab, a swab isused to wipe the particles from the fan blade surface, or a solution ismanually applied to the fan blades to elute the particles off the fanblade surface. This is a time-consuming process that is impractical forreal-time threat assessment.

SUMMARY OF THE INVENTION

A particle collection apparatus is configured to collect airborneparticles into a liquid solution. In some embodiments, the particles arecollected from an airflow provided by an air collector and/ or aparticle detection apparatus. The particle collection apparatus includesa fan assembly, for example a muffin fan, and in some embodiments afluid collector apparatus. The fluid collector apparatus is coupled to acollection vessel via one or more drain lines.

Fan blades within the fan assembly are rotated in a first rotationaldirection, thereby generating airflow from above the fan blades downwardpast the fan blades. The airborne particles adhere to the surface of thefan blades, hub, and fan housing as the air flows past. In this manner,particles are collected on the surfaces of the fan for a predeterminedperiod of time. When the particle collection is completed, the fandirection is reversed to a second rotational direction and maintained ata relatively low rotational rate.

A fluid, such as a rinse buffer, is slowly dispensed onto the hub of thefan blades. Due to the centripetal force of the spinning fan blades, thefluid is spread thin across the top surface of the fan blades and theliquid film washes the blade of the fan, removing particulates from thefan blade. The solution is pushed outward against the inner wall of thefan housing forming a fluid meniscus.

The fluid meniscus is contained between the spinning fan blades and theinner wall of the fan housing. The fluid surface tension and the upwardairflow caused by the fan blades rotating in the second rotationaldirection prevents the fluid meniscus from dripping downward.

Once the fluid is forced against the inner wall of the fan housing toform the fluid meniscus, the fan speed is increased in the secondrotational direction. The centripetal force from the fan blades pushesthe fluid contained in the fluid meniscus over the fan housing wall andinto an annular reservoir of the fluid collector apparatus. Thecollected fluid is then vacuumed and consolidated into the collectionvessel, where it can be subsequently analyzed.

In some embodiments, the fluid collector apparatus is eliminated anddrain holes are drilled directly into the wall of the fan housing. Thedrains holes are positioned proximate to the outer edges of the fanblades. Drain lines are connected to the drain holes. The fluid, orfluid meniscus if one is formed, drains through the drain holes into thedrain lines, and is consolidated in the collection vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an exemplary detection system.

FIG. 2 illustrates a perspective view of the particle collectionapparatus according to a first embodiment of the present invention.

FIG. 3 illustrates a cut-out side view of the particle collectionapparatus.

FIG. 4 illustrates the particle collection apparatus in the second phaseof operation.

FIG. 5 illustrates the particle collection apparatus in a third phase ofoperation.

FIG. 6 illustrates the particle collection apparatus including acompressed air nozzle.

FIG. 7 illustrates a method of operating the particle collectionapparatus.

FIG. 8 illustrates a cut-out side view of a second embodiment of theparticle collection apparatus.

FIG. 9 illustrates a method of operating the second embodiment of theparticle collection apparatus.

Embodiments of the particle collection apparatus are described relativeto the several views of the drawings. Where appropriate and only whereidentical elements are disclosed and shown in more than one drawing, thesame reference numeral will be used to represent such identicalelements.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIG. 1 illustrates a block diagram of an exemplary detection system 2.The detection system 2 includes an air collector and particle detectionmodule 4, a processing module 6, and a particle collection apparatus 10.The air collector and particle detection module 4 intakes air from theambient and measures particular characteristics of the particles withinthe air, for example the reflectance characteristics. The processingmodule 6 is configured to provide automated control of the air collectorand particle detection module 4 and the particle collection apparatus10. The processing module 6 also receives the measured characteristicsfrom the air collector and particle detection module 4 and determines ifthe measured characteristics match predetermined thresholds. Forexample, the processing module determines if measured reflectancecorresponds to a specific wavelength of light. A trigger signal isgenerated by the processing module 6 if the measured characteristicsmatch the predetermined thresholds. The trigger signal activates theparticle collection apparatus 10. In one embodiment, the particlecollection apparatus 10 is integrated within the detection system 2, asis shown in FIG. 1. Alternatively, the particle collection apparatus 10is a separate unit from the detection system, and the particlecollection apparatus 10 is coupled to the detection system such that airpassing through the detection system is directed to the particlecollection apparatus 10, such as via an air duct, when the triggersignal is generated.

FIG. 2 illustrates a perspective view of the particle collectionapparatus 10 according to a first embodiment of the present invention.The particle collection apparatus 10 includes a fan assembly 20, a fluidcollector 30, a fluid dispensing tube 40, a fluid dispensing module 42,one or more drain tubes 50, a collection vessel 60, and a vacuum 62.

FIG. 3 illustrates a cut-out side view of the particle collectionapparatus 10. The fan assembly 20 includes fan blades 24 coupled to afan motor 26 within a fan housing 22. The fan housing 22 includes anupper rim 28 within which the fan blades 24 rotate. The fluid collector30 is coupled to the fan housing 22 such that a reservoir 32 within thefluid collector 30 is positioned below the upper rim 28. In oneembodiment, the reservoir 32 is configured as an annular reservoirpositioned at the outer perimeter of the upper rim 28. A bottom surface36 of the reservoir 32 includes one or more holes 34. A drain tube 50 iscoupled to each hole 34.

The particle collection apparatus 10 is shown in FIG. 3 while in a firstphase of operation. When first activated by the trigger signal, the fanmotor 26, and therefore the fan blades 24, rotate in a first rotationaldirection, thereby drawing air from the air collector and particledetection module 4 through the fan assembly 20.

The fan blades 24 are configured such that when rotated in the firstrotational direction, airflow is generated in a direction from the aircollector and particle detection module 4 towards the top surface of thefan blades 24. In relation to FIG. 3, rotating the fan blades 24 in thefirst rotational direction, which in this case is clockwise, causes theairflow to move from the top of the page above the fan blades 24, downpast the fan blades 24 As the airflow moves past the fan blades 24,particles 60 within the airflow accumulate on the top surface of the fanblades 24.

Under control of the processing module 6, the fan motor 26 rotates inthe first rotational direction for an amount of time and a rotationalspeed sufficient for a detectable amount of particles 60 to collect onthe fan blades 24. This amount of time and rotational speed ispredetermined. After the predetermined amount of time, a second phase ofoperation is performed in which the rotational direction of the fanmotor 26 is reversed to a second rotational direction at a rotationalspeed reduced relative to the rotational speed in the first direction.

FIG. 4 illustrates the particle collection apparatus 10 in the secondphase of operation. While in the second phase, the fan motor 26, andtherefore the fan blades 24, rotate in the second rotational direction,which in this case is counter-clockwise. As a result, the airflow isreversed, moving from the bottom up as related to FIG. 4.

The fluid dispensing tube 40 dispenses fluid from the fluid dispensingmodule 42 onto the fan blades 24. In some embodiments, the fluid iswater or water-based. Alternatively, the fluid is any fluid that doesnot damage the particles 60. The fluid dispensing module 42 regulatesthe amount of fluid that is dispensed by the fluid dispensing tube 40.The fluid is dispensed onto the center, or hub, of the fan blades 24.Due to the centripetal force of the rotating fan blades 24, the fluidspreads from the center of the fan blades 24 toward the out edge of thefan blades 24, thereby providing a liquid film over the top surface ofthe fan blades 24. During this step, the second rotational direction ismaintained at a first speed. The first speed is low enough that thefluid maintains contact with the fan blades, but high enough that thefluid does not fly off the fan blades.

The speed in the second rotational direction is then increased to asecond speed. The increased speed results in increased centripetal forceapplied to the fluid on the fan blades 24. This increased centripetalforce forces the fluid to move to the outer edge of the fan blades 24,in the process removing collected particulates from the surface of thefan blades 24. In this manner, a wiping action is performed, whereby theparticles accumulated on the surface of the fan blades are wiped off bycentripetal force applied to the fluid.

The fluid is pushed outward against an inner wall of the fan housing 22,thereby forming a fluid meniscus 70. The fluid meniscus 70 is containedbetween the outer edges of the spinning fan blades 24 and the inner wallof the fan housing 22. By rotating the fan blades at the proper secondspeed, the upward airflow caused by the fan blades rotating in thesecond rotational direction along with the fluid surface tensionsubstantially prevents the fluid meniscus 70 from dripping downward. Assuch, the second speed is low enough that the fluid does not fly off thefan blades 24, but the second speed is high enough to force the fluid tothe inner wall of the fan housing 22 and high enough to generatesufficient upward airflow to form the fluid meniscus 70 and prevent thefluid from dripping downward of the fan blades 24.

In some embodiments, the second phase of operation is performed using asingle speed, instead of the first speed and the second speed asdescribed above. The single speed is low enough to prevent fluid fromflying off the fan blades 24, but high enough to force the fluid to theinner wall of the fan housing 22 and to form the fluid meniscus 70.

FIG. 5 illustrates the particle collection apparatus 10 in a third phaseof operation. In the third phase, the speed in the second rotationaldirection is increased to a third speed. The third speed generatescentripetal force sufficient to force the fluid in the fluid meniscus 70over the upper rim 28 of the fan housing 22 and into the reservoir 32 ofthe fluid collector 30. As a result, the fluid 72 collects in thereservoir 32. The fluid collector 30 is composed of a hydrophobicmaterial such that fluid contacting the wall of the fluid collector 30settles in the reservoir 32. Alternatively, the fluid collector 30 iscomposed of any non-absorbent material.

Vacuum is applied to the drain tubes 50 by the vacuum 62 so that thefluid collected in the reservoir 32 is drawn through the holes 34, intothe drain tubes 50, and into the collection vessel 60. In oneembodiment, vacuum is applied to the drain tubes 50 when the fan motor26 is increased to the third speed at the onset of the third phase.Alternatively, vacuum is applied to the drain tubes 50 during the secondphase and the third phase of operation. Still alternatively, vacuum isapplied to the drain tubes 50 any time the fan motor 26 rotates in thesecond rotational direction.

A single pass is referred to as performing the first phase, the secondphase, and the third phase of operation. One or more passes can beperformed to collect a larger percentage of the particles from the fanblades 24 and/or to increase the fluid sample size collected in thecollection vessel 60. A maximum amount of fluid that can be dispensedonto the fan blades 24 during each pass is determined by the dimensionsof the fan blade assembly 20, the material of the fan blades 24 and thefan housing 22, the viscosity and surface tension of the fluid, and thespeeds necessary to perform the second operation and the thirdoperation. If the amount of fluid dispensed onto the fan blades 24exceeds the maximum amount, then the fluid meniscus 70 does not properlyform and a significant portion of the fluid flows off the fan blades 24and into the fan housing 22. This fluid, and the particles containedtherein, are lost and unable to be collected in the fluid collector 30.

FIG. 6 illustrates the first embodiment of the particle collectionapparatus 10 including a compressed air nozzle 72. The compressed airnozzle 72 is positioned at an angle to the reservoir 32 such that airoutput from the air nozzle 72 generates a vortex within the reservoir32. The air forces fluid trapped between drain holes toward adjacentdrain holes. In this manner, residual fluid in the reservoir 32 ispushed towards proximate holes 34.

FIG. 7 illustrates a method of operating the particle collectionapparatus 10. At the step 100, the fan blades 24 are rotating in thefirst rotational direction. Rotating the fan blades 24 in the firstrotational direction generates an airflow from above the fan blades 24towards the fan blades 24. At the step 110, particles within the airfloware collected on the fan blades. As the airflow generated at the step100 flows past the fan blades 24, particles within the airflow adhere tothe surface of the fan blades 24. At the step 120, the spin direction ofthe fan blades 24 is reversed such that the fan blades are rotating inthe second rotational direction. Rotation of the fan blades 24 in thesecond rotational direction generates an airflow from beneath the fanblades 24 toward the fan blades 24. The rotational spin rate of the fanblades 24 in the second rotational direction is set to a first speed. Atthe step 130, fluid is dispensed onto a hub of the fan blades 24 whilerotating at the first speed. The centripetal force generated whilerotating at the first speed forces the fluid into a liquid film over thetop surface of the fan blades 24. At the step 140, the rotational spinrate of the fan blades 24 in the second rotational direction isincreased to a second speed. The additional centripetal force generatedwhile rotating at the second speed forces the fluid and the particles onthe surface of the fan blades 24 to the outer edges of the fan blades24. A fluid meniscus is formed between the edge of the fan blades 24 anthe inner wall of the fan housing 22. The fluid meniscus includes thefluid and the particles.

In an alternative embodiment, the step 120 and the step 140 are combinedinto a single step such that when the spin direction of the fan blades24 is reversed to rotate in the second rotational direction, therotational spin rate of the fan blades 24 in the second rotationaldirection is set to the second speed. In this alternative embodiment,the fluid is dispensed onto the fan blades 24 while the fan blades 24are rotating at the second speed in the second rotational direction, andthe fluid is forced to the edge of the fan blades 24 to form the fluidmeniscus.

At the step 150, the rotational spin rate of the fan blades 24 in thesecond rotational direction is increased to a third speed. Theadditional centripetal force generated while rotating at the third speedforces the fluid meniscus over the upper rim 28 and into the fluidcollector 30. At the step 160, a vacuum is applied to the drain tubes 50that are coupled to the fluid collector 30. The vacuum draws the fluidcollected in the fluid collector 30 through the drain tubes 50 and intothe collection vessel 60. At the step 170, the step 130 through 160 arerepeated as many times as deemed necessary to sufficiently elute theparticles 60 from the surface of the fan blades 24.

The fan blades 24 are composed of any material to which one or moretypes of particles to be collected will adhere. In some embodiments, thefan blades are composed of plastic. Alternatively, the fan blades 24 arecoated with any material to which one or more types of particles to becollected will adhere.

FIG. 8 illustrates a cut-out side view of the particle collectionapparatus according to a second embodiment of the present invention. Inthe second embodiment, the fluid collector 30 of the first embodiment iseliminated. Drain holes 80 are drilled through the wall of the fanhousing 22 proximate to the fan blades 24. In some embodiments, thedrain holes 80 are positioned substantially in the plane of the fanblades 24. Alternatively, the position of the drain holes 80 can bemoved up or down relative to the plane of the fan blades so as toimprove the collection of the fluid through the drain holes 80. One ofthe drain tubes 50 is coupled to each of the drain holes 80.

The second embodiment of the particle collection apparatus operates intwo phases. The first phase is identical to the first phase of the firstembodiment in which the fan motor 26 and the fan blades 24 rotate in thefirst rotational direction to collect particles on the fan blades 24.FIG. 8 illustrates the second embodiment of the particle collectionapparatus in the second phase of operation. While in the second phase,the fan motor 26, and therefore the fan blades 24, rotate in the secondrotational direction, which in this case is counter-clockwise. As aresult, the airflow is reversed, moving from the bottom up as related toFIG. 8.

The fluid dispensing tube 40 dispenses fluid from the fluid dispensingmodule 42 onto the fan blades 24. The fluid is dispensed onto thecenter, or hub, of the fan blades 24. Due to the centripetal force ofthe rotating fan blades 24, the fluid is forced from the center of thefan blades 24 toward the inner wall of the fan housing 22, in theprocess removing collected particulates from the surface of the fanblades 24. The rotational speed during this second phase is low enoughto prevent fluid from flying off the fan blades 24, but high enough toforce the fluid to the inner wall of the fan housing 22.

Vacuum is applied to the drain tubes 50 by the vacuum 62 so that thefluid forced toward the inner wall of the fan housing 22 is drawnthrough the drain holes 80, into the drain tubes 50, and into thecollection vessel 60. Vacuum is applied to the drain tubes 50 during thesecond phase of operation. One or more passes can be performed tocollect a larger percentage of the particles from the fan blades 24and/or to increase the fluid sample size collected in the collectionvessel 60.

In some embodiments, the second phase is performed using two separatesteps. During the first step, the fluid is dispensed onto the fan blades24 and spreads from the center of the fan blades toward the outer edgeof the fan blades, thereby providing a liquid film over the top surfaceof the fan blades 24. During this step, the second rotational directionis maintained at a first speed. The first speed is low enough that thefluid maintains contact with the fan blades, but high enough that thefluid does not fly off the fan blades. The speed in the secondrotational direction is then increased to a second speed. The increasedspeed results in increased centripetal force applied to the fluid on thefan blades 24. This increased centripetal force forces the fluid to moveto the outer edge of the fan blades 24.

In some embodiments, vacuum is not applied to the drain lines 50 duringthis second phase. Instead, the fluid is pushed outward against theinner wall of the fan housing 22, thereby forming the fluid meniscus 70,as in the first embodiment. The fluid meniscus 70 is contained betweenthe outer edges of the spinning fan blades 24 and the inner wall of thefan housing 22. By rotating the fan blades at the proper speed, theupward airflow caused by the fan blades rotating in the secondrotational direction along with the fluid surface tension substantiallyprevents the fluid meniscus 70 from dripping downward. As such, therotational speed is low enough that the fluid does not fly off the fanblades 24, but the second speed is high enough to force the fluid to theinner wall of the fan housing 22 and high enough to generate sufficientupward airflow to form the fluid meniscus 70 and prevent the fluid fromdripping downward of the fan blades 24. Subsequent to forming the fluidmeniscus 70, and while maintaining rotation of the fan blades 24 in thesecond rotational direction, vacuum is applied to the drain lines 50 andthe fluid meniscus 70 drains through the drain holes 80. It isunderstood that a portion of the fluid meniscus 70 may drain through thedrain holes 80 prior to application of the vacuum.

FIG. 9 illustrates a method of operating the second embodiment of theparticle collection apparatus 10. At the step 200, the fan blades 24 arerotating in the first rotational direction. Rotating the fan blades 24in the first rotational direction generates an airflow from above thefan blades 24 towards the fan blades 24. At the step 210, particleswithin the airflow are collected on the fan blades 24. As the airflowgenerated at the step 200 flows past the fan blades 24, particles withinthe airflow adhere to the surface of the fan blades 24. At the step 220,the spin direction of the fan blades 24 is reversed such that the fanblades are rotating in the second rotational direction. Rotation of thefan blades 24 in the second rotational direction generates an airflowfrom beneath the fan blades 24 towards the fan blades 24. At the step230, a vacuum is applied to the drain tubes 50 that are coupled to thedrain holes 80. At the 240, fluid is dispensed onto a hub of the fanblades 24 while rotating in the second rotational direction. Thecentripetal force generated while rotating in the second rotationaldirection forces the fluid and the particles on the surface of the fanblades 24 to the outer edges of the fan blades 24 and to the inner wallof the fan housing 22. At the step 250, the vacuum applied to the draintubes 50 draws the fluid forced toward the inner wall of the fan housing22 through the drain holes 80, the drain tubes 50 and into thecollection vessel 60. At the step 260, the step 240 through 250 arerepeated as many times as deemed necessary to sufficiently elute theparticles 60 from the surface of the fan blades 24.

In an alternative embodiment, the step 230 is performed after the step240. In this manner, vacuum is not applied to the drain tubes 50 untilafter a fluid meniscus is formed between the edge of the fan bladed 24and the inner wall of the fan housing 22.

The particle collection apparatus 10 is automated to collect a fluidsample that includes the particles eluted from the surface of the fanblades. The processing module 6 controls the automated functionsassociated with performing the first phase, the second phase, and thethird phase described above. In this manner, airborne particles can beautomatically collected into a liquid solution. In alternativeembodiments, operation of the particle collection apparatus can bemanually performed, either in part or in full.

As described herein, the term “speed” is a relative term. The thirdspeed is faster than the second speed, and the second speed is fasterthan the first speed. Each of the actual speeds is dependent on manyfactors, including but not limited to, the size of the fan blades, theamount of fluid dispensed onto the fan blades, the distance between theouter perimeter of the fan blades and the inner wall of the fan housing,the height of the fan housing rim relative to the fan blades, and thetype of fluid used. For a specific fan assembly and fluid, the actualfirst speed, second speed, and third speed are experimentallydetermined.

The particle collection apparatus is described above in relation to abio-threat application. It is understood that the particle collectionapparatus can also be used to collect non-harmful air particles and ingeneral the particle collection apparatus can be used to collect anyparticles that collect on the surface of a fan blade. It is alsounderstood that the particle collection apparatus can used within asystem, such as the bo-threat detection system described above, or theparticle collection apparatus can be used as a stand alone device.

The present invention has been described in terms of specificembodiments incorporating details to facilitate the understanding of theprinciples of construction and operation of the invention. Suchreference herein to specific embodiments and details thereof is notintended to limit the scope of the claims appended hereto. It will beapparent to those skilled in the art that modifications may be made inthe embodiment chosen for illustration without departing from the spiritand scope of the invention.

1. A method of collecting airborne particles into a liquid solution, themethod comprising: a. rotating fan blades in a first rotationaldirection, thereby generating airflow past the fan blades in a firstdirection, wherein the airflow includes particles to be collected; b.collecting the particles on the fan blades while rotating the fan bladesin the first rotational direction; c. rotating the fan blades in asecond rotational direction at a first speed, thereby generating airflowpast the fan blades in a second direction; d. dispensing a fluid ontothe fan blades while rotating the fan blades at the first speed, whereinthe fluid and the particles are centripetally forced to the edge of thefan blades; and e. rotating the fan blades in the second rotationaldirection at a second speed, thereby forcing the fluid and the particlesinto a fluid collector.
 2. The method of claim 1 further comprisingforming a fluid meniscus of the fluid and particles forced to the edgeof the fan blades, wherein the fluid meniscus is formed between the edgeof the fan blades and an inner wall of a fan housing.
 3. The method ofclaim 2 wherein the fluid meniscus is formed by a surface tension of thefluid and the airflow moving in the second direction.
 4. The method ofclaim 3 wherein the second direction is perpendicular to the fan blades.5. The method of claim 1 further comprising generating a trigger signal,wherein the trigger signal initiates rotating the fan blades in thefirst rotational direction.
 6. The method of claim 1 further comprising:a. coupling one or more drain lines to the fluid collector; and b.applying a vacuum to the one or more drain lines to draw the fluid fromthe fluid collector into a collection vessel.
 7. The method of claim 6further comprising blowing air across the fluid collector to forceresidual fluid toward the one or more drain line.
 8. The method of claim1 wherein rotating the fan blades at the first speed, dispensing thefluid onto the fan blades, and rotating the fan blades at the secondspeed comprises a single pass, and the method further comprisesperforming multiple passes.
 9. The method of claim 1 further comprisingrotating the fan blades in the second rotational direction at a thirdspeed, thereby forcing the fluid and the particles to the edge of thefan blades, wherein the third speed is faster than the first speed andslower than the second speed.
 10. A method of collecting airborneparticles into a liquid solution, the method comprising: a. rotating fanblades in a first rotational direction, thereby generating airflow pastthe fan blades in a first direction, wherein the airflow includesparticles to be collected; b. collecting the particles on the fan bladeswhile rotating the fan blades in the first rotational direction; c.rotating the fan blades in a second rotational direction at a firstspeed, thereby generating airflow past the fan blades in a seconddirection; d. dispensing a fluid onto the fan blades while rotating thefan blades at the first speed, wherein the fluid and the particles arecentripetally forced to the edge of the fan blades; e. coupling one ormore drain lines proximate to a circumference of the rotating fanblades; and f. applying vacuum to the one or more drain lines to drawfluid from the edge of the fan blades into a fluid collector.
 11. Themethod of claim 10 wherein rotating the fan blades in a secondrotational direction at a first speed and dispensing the fluid onto thefan blades comprises a single pass, and the method further comprisesperforming multiple passes.
 12. An apparatus to collect airborneparticles into a liquid solution, the apparatus comprising: a. a fanassembly including a fan motor coupled to one or more fan blades,wherein the fan motor is configured to rotate in a first rotationaldirection thereby generating airflow past the fan blades in a firstdirection, wherein the airflow includes particles that adhere to the fanblades, and to rotate in a second rotational direction therebygenerating airflow past the fan blades in a second direction; b. a fluiddispensing tube configured to dispense fluid onto the fan blades whilethe fan motor is rotating in the second rotational direction, therebyforcing the fluid and the particles to an outer edge of the fan blades;and c. a fluid collector coupled to the fan assembly to collect thefluid and particles forced from the fan blades.
 13. The apparatus ofclaim 12 wherein the fluid collector includes one or more holes, eachhole coupled to a drain line, and the apparatus further comprises acollection vessel coupled to the drain lines.
 14. The apparatus of claim13 further comprising a vacuum coupled to the collection vessel to applyvacuum to the drain lines.
 15. The apparatus of claim 12 furthercomprising an air nozzle configured to direct air across the fluidcollector to force residual fluid toward the one or more holes.
 16. Theapparatus of claim 12 wherein the fluid dispensing tube is positioned todispense fluid onto a hub of the fan blades.
 17. The apparatus of claim12 wherein the fan motor is configured to operate at a first speed, asecond speed, and a third speed in the second rotational direction,wherein the third speed is faster than the second speed, and the secondspeed is faster than the first speed.
 18. The apparatus of claim 17wherein the fan motor is configured to operate at the first speed whiledispensing fluid onto the fan blades, to operate at the second speed toforce the fluid and the particles to the outer edge of the fan blades,and to operate at the third speed to force the fluid and particles intothe fluid collector.
 19. The apparatus of claim 12 wherein the fan motoris configured to operate at a first speed and a second speed in thesecond rotational direction, wherein the second speed is faster than thefirst speed.
 20. The apparatus of claim 19 wherein the fan motor isconfigured to operate at the first speed while dispensing fluid onto thefan blades and to force the fluid and the particles to the outer edge ofthe fan blades, and to operate at the second speed to force the fluidfrom the outer edge of the fan blades into the fluid collector.
 21. Theapparatus of claim 12 wherein the fan assembly further comprises a fanhousing including an upper rim.
 22. The apparatus of claim 21 whereinthe fluid collector includes a reservoir, further wherein the fluidcollector is coupled to the fan assembly such that the reservoir ispositioned below a level of the upper rim.
 23. The apparatus of claim 12further comprising a fluid dispensing module to regulate the fluiddispensed from the fluid dispensing tube.
 24. The apparatus of claim 23further comprising a processing module coupled to the fan assembly andto the fluid dispensing module to automatically operate the apparatus.25. The apparatus of claim 12 wherein the fan blades comprise a materialto which the particles adhere.
 26. The apparatus of claim 12 wherein thefan blades including a coating comprised of a material to which theparticles adhere.
 27. A system to collect airborne particles into aliquid solution, the apparatus comprising: a. a particle collectionapparatus comprising: i. a fan assembly including a fan motor coupled toone or more fan blades, wherein the fan motor is configured to rotate ina first rotational direction thereby generating airflow past the fanblades in a first direction, wherein the airflow includes particles thatadhere to the fan blades, and to rotate in a second rotational directionthereby generating airflow past the fan blades in a second direction;ii. a fluid dispensing tube configured to dispense fluid onto the fanblades while the fan motor is rotating in the second rotationaldirection, thereby forcing the fluid and the particles to an outer edgeof the fan blades; and iii. a fluid collector coupled to the fanassembly to collect the fluid and particles forced from the fan blades;and b. a processing module coupled to the fan assembly and to the fluiddispensing tube to provide control signals to control the rotation ofthe fan motor and to dispense the fluid from the fluid dispensing tube.28. The system of claim 27 wherein the fluid collector includes one ormore holes, each hole coupled to a drain line, and the system furthercomprises a collection vessel coupled to the drain lines.
 29. The systemof claim 28 further comprising a vacuum coupled to the collection vesselto apply vacuum to the drain lines.
 30. The system of claim 28 furthercomprising an air nozzle configured to direct air across the fluidcollector to force residual fluid toward the one or more holes.
 31. Thesystem of claim 27 wherein the fluid dispensing tube is positioned todispense fluid onto a hub of the fan blades.
 32. The system of claim 27wherein the fan motor is configured to operate at a first speed, asecond speed, and a third speed in the second rotational direction,wherein the third speed is faster than the second speed, and the secondspeed is faster than the first speed.
 33. The system of claim 32 whereinthe fan motor is configured to operate at the first speed whiledispensing fluid onto the fan blades, to operate at the second speed toforce the fluid and the particles to the outer edge of the fan blades,and to operate at the third speed to force the fluid and particles intothe fluid collector.
 34. The system of claim 27 wherein the fan motor isconfigured to operate at a first speed and a second speed in the secondrotational direction, wherein the second speed is faster than the firstspeed.
 35. The system of claim 34 wherein the fan motor is configured tooperate at the first speed while dispensing fluid onto the fan bladesand to force the fluid and the particles to the outer edge of the fanblades, and to operate at the second speed to force the fluid from theouter edge of the fan blades into the fluid collector.
 36. The system ofclaim 27 wherein the fan assembly further comprises a fan housingincluding an upper rim.
 37. The system of claim 36 wherein the fluidcollector includes a reservoir, further wherein the fluid collector iscoupled to the fan assembly such that the reservoir is positioned belowa level of the upper rim.
 38. The system of claim 27 further comprisinga fluid dispensing module to regulate the fluid dispensed from the fluiddispensing tube.
 39. The system of claim 38 further comprising aprocessing module coupled to the fan assembly and to the fluiddispensing module to automatically operate the apparatus.
 40. The systemof claim 27 wherein the fan blades comprise a material to which theparticles adhere.
 41. The system of claim 27 wherein the fan bladesincluding a coating comprised of a material to which the particlesadhere.
 42. An apparatus to collect airborne particles into a liquidsolution, the apparatus comprising: a. a fan assembly including a fanhousing and a fan motor coupled to one or more fan blades, wherein thefan motor is configured to rotate in a first rotational directionthereby generating airflow past the fan blades in a first direction,wherein the airflow includes particles that adhere to the fan blades,and to rotate in a second rotational direction thereby generatingairflow past the fan blades in a second direction, further wherein thefan housing includes one or more drain holes positioned proximate to anouter edge of the fan blades; and b. a fluid dispensing tube configuredto dispense fluid onto the fan blades while the fan motor is rotating inthe second rotational direction, thereby forcing the fluid and theparticles to the outer edge of the fan blades and into the one or moredrain holes.
 43. The apparatus of claim 42 further comprising a drainline coupled to each drain hole, and the apparatus further comprises acollection vessel coupled to the drain lines.
 44. The apparatus of claim43 further comprising a vacuum coupled to apply vacuum to the drainlines.
 45. The apparatus of claim 42 wherein the fluid dispensing tubeis positioned to dispense fluid onto a hub of the fan blades.
 46. Theapparatus of claim 42 further comprising a fluid dispensing module toregulate the fluid dispensed from the fluid dispensing tube.
 47. Theapparatus of claim 46 further comprising a processing module coupled tothe fan assembly and to the fluid dispensing module to automaticallyoperate the apparatus.
 48. The apparatus of claim 42 wherein the fanblades comprise a material to which the particles adhere.
 49. Theapparatus of claim 42 wherein the fan blades including a coatingcomprised of a material to which the particles adhere.